1912] Wiegand,— Amelanchier in eastern North America — 137 
below on the very young fruit:: sepals revolute from the middle at 
the time when the petals fall. 
C. Margins of the leaf forming an angle at the apex: petals narrow or 
broad. 
D. 
DD. 
Petals 11-20 mm. long, narrow: sepals 4 mm. long: hypanthium 
very open and flat: racemes more or less drooping: leaves oval- 
orbicular; upper veins, in typical specimens, running straight 
to the apex of the coarse spreading sharp teeth (not so in the 
var.): scrawny, slender, often arching, p 1.0-2.5 m. high; 
stems solitary or few together. A. sanguinea. 
Petals 7-10 mm. long, broad: sepals 2-3 "x mm. long: hy- 
panthium deeper: racemes erect or nearly so: leaves oval- 
oblong; veins usually becoming irregular just before reaching 
the margin; teeth less conspicuous, because of shorter acumina- 
tions, and more ascending, sometimes confined to the apex: more 
stiffly upright shrubs 0.3-1.2 m. high, growing in colonies (not 
clumps) from rhizome-like bases. 2. A. humilis. 
CC. Margins of the leaf forming a rounded or sub-truncate, rarely 
retuse, apex; blade broadly oval or oblong-oval; tay irregular 
near the margin; teeth usually fewer. A. florida. 
BB. Teeth of the leaves fine (5-12 per cm. on average E. veins 
irregular, unequally distant, usually with frequent intermediate 
shorter ones (Pyrus-like); summit of the ovary, etc. various. 
C. Leaves densely white-tomentose when young, becoming green; 
lower pedicels 7-18 mm. long, in fruit 10-25 mm. long. 
Leaves rounded at the apex (rarely subacute): hypanthium 
large at flowering time, 3-5 mm. in diam.: sepals narrow, 
triangular or lanceolate, acute, erect or recurved from the middle 
at the time when the petals fall: petals short, 7-9 mm. long: 
shrubs. 
E. Hypanthium saucer-shaped, constricted below on the very 
young fruit: sepals recurved from the middle when the petals 
fall: summit*of the ovary woolly, at least when young: leaves 
oval; veins 7-11 (average 8-9) pairs; teeth on average leaves 
20-28 (32) on each side: stems 0.3-1.2 m. high, forming col- 
onies as in A. humilis. 4. A. stolonifera. 
EE. Hypanthium campanulate, not constricted below on the young 
DD. 
fruit: sepals mostly erect: summit of the ovary glabrous, 
rarely slightly woolly: leaves oblong; veins 10-15 (average 
11-13) pairs; teeth finer, (20) 25—40 (45) on each side: stems 
1.2-8 m. high, forming alder-like clumps. 5. A. oblongifolia. 
Leaves short-acuminate: hypanthium small, 2.5-3 (3.5) mm. 
diam., campanulate, not constricted below on the young fruit: 
sepals broad, oblong-triangular, obtuse or abruptly acute or 
abruptly short-acuminate, reflexed from the base when the petals 
fall: summit of the ovary glabrous: petals elongated, 10-14 mm. 
long; shrubs or trees. 6. A. canadensis. 
CC. Leaves nearly or quite glabrous from the first, ovate, oval, or 
1In some species of Amelanchier (A. sanguinea, humilis, florida, stolonifera, and 
Bartramiana), as the fruit matures, the hypanthium remains on the summit in almost 
its original saucer-shaped form during the period of growth just subsequent to the 
falling of the petals. Between the hypanthium and the ovary, in this case, there is 
therefore, a conspicuous constriction at this period. In other species (A. canadensis 
and laevis) the ovary seems to grow up into the hypanthium so that the latter is 
stretched around the summit of the young fruit. The constriction in these cases is, 
therefore, much less, or none at all. The condition in A. oblongifolia is somewhat 
intermediate. 
As the fruit grows older these distinctions become much less marked. 
